Improvement in steam-engine valves



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Steam-Engine Valve.

Patented April 20, 1875.

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RUDOLPH SCHMIDT, OF YONKEBS, NEW YORK.

Specification forming part of Letters Patent No. 162,196, dated April20, 1875; application filed February 20, 1875.

To all whom it may concern:

Be it known that I, RUDOLPH SCHMIDT, of the city of Yonkers, county ofWestchester and State of New York, have invented a new and improvedvalve for distributing the motive fluid for a reciprocating motion of anengine-piston; and I do hereby declare that the following is a full,clear, an d exact description thereof, which will enable others skilledin the art to make and use the same, reference being had to theaccompanying drawing, formin g part of this specification.

The invention relates to the arrangement and device of pawls ormechanical equivalents placed inside of the main ports of theengine-cylinder, by which a distributing-valve is locked in the properposition for distributin g the motive fluid, until the main piston atthe end of the stroke, or after a certain part of it is completed,releases the said distributing-valve from the action of the pawl, andallows it to move over into the proper position for distributing themotive fluid for the return strokea position in which it is kept by theaction of the pawl, until the return stroke is completed, when it isreleased and moves back into the original position.

Figure 1 represents a vertical section of the cylinder of a steam-pumpor water-pressure engine. Fig. 3 is a vertical section of the engine-cylinder, showing the valve in position for the right-hand strokeof the engine. Fig. 2 shows the arrangement as applied to the ordinaryslide-valve of direct-acting steampumps.

Similar letters of reference in dicate like parts.

A represents the main cylinder. B is the main piston, which is connectedtothe piston of the pump, as is usual in direct-actin g steampumps. candf are the supply-ports for the engine-cylinder. e and e are outlets,which lead into the free air, or into a space of less pressure than themotive fluid. The distributing-valve consists of thethree pistons on onerod, marked P, P, and p, and moved by the diflerential pressure-anarrangement for which Letters Patent have been granted to me, dated the6th day of August, in the year of our Lord 1867. The steam enters at S,between the large piston P and small piston 11. The space between P andP is always connected with the outlet 0. The space U is connected withthe port 0 on the left-hand side of the piston B by a port marked g.

The action of the valve is the following: The valve, as shown in Fig. 3,is in its proper position to distribute the motive fluid for the stroketoward the right. The steam enters through the port 0 on the left sideof the piston B, passing at the same time into the space U. The pressureon the large pistons P and P being equal and balanced, the valve has atendency to move toward the right, due to the pressure of the motivefluid on the area of the small piston 2,- but the pawl m keeps it inposition till it is released by the main piston B striking the pawl m.The valve now moves over into the position shown in Fig. l, in which itis locked by the pawl a. A quick action of the pawls may be insured invarious ways. Ihave deemed it the best to make the end against which themain piston strikes heavy, so as to give the pawl a tendency to enterinto the valve-cylinder. The same result might be obtained by springs oreven by using the impact of the exhausting motive fluid. The valve isnow in position to distribute the motive fluid for the return stroke.The port f is connected with S, and the motive fluid enters theright-hand side of the piston, and impels the piston toward the left.The motive fluid on the left-hand side is exhausted through the port 0and the outlet 0, and the distributingvalve is ready to move toward theleft by a pressure due to the difference of the areas of the smallpiston 19 and large piston 1 The motive fluid is released out of thespace U by passing out through the ports 9, c, and e. As soon as themain piston strikes pawl end a the valve is released and moves back intoits original position, where it is kept by the pawl m catching it. Arepetition of the action, as described above, causes the reciprocatingmotion of the main piston to perform the useful work for which it isintended.

I am aware that look arrangements for looking cut-oft valves by means ofpawls or mechanical equivalents have been used for preventing the valveto shut off the steam until a certain part of the stroke is completed. Iam alsoa-ware that such arrangements have been used for looking adistributing-valve actuated only in one direction by a constant pressureof steam, but moved in the opposite direction by a mechanicalarrangement attached to the pistourod, as in the Nasmyth steam-hammer;but I am not aware that (listributing-valves have been locked by pawlsplaced in the main ports of the main cylinder, and reaching with thepawl end into the valvechest, for the purpose of locking the valve inthe proper position for distributing the motive fluid, and releasing itafter a part of the stroke is c0mpleted,to be moved over by the pressureof the motive fluid into the proper position for the return stroke.

RUDOLPH SGHMIDT.

Witnesses:

J. H. BROWN, J. M. ALVORD.

